Perhaps the highlight of the announcement today was that the company will be releasing its Roslyn compiler stack as open source under the Apache 2.0 license. Roslyn includes a C# and Visual Basic.NET compiler, offering what Microsoft calls a "compiler as a service".

This is more than just a code dump - Microsoft is launching the .NET Foundation, with representatives from Microsoft, GitHub, and Xamarin, among others, to act as stewards for the various related open source projects.

Did they also change their patent stance? Without a legal right to use MS's patents, open sourcing the code is fairly useless to most devs. And no, an "assurance" from the PR department is not a legal right to use a patent.

Did they also change their patent stance? Without a legal right to use MS's patents, open sourcing the code is fairly useless to most devs. And no, an "assurance" from the PR department is not a legal right to use a patent.

They licensed Roslyn (and most of their Open Source code over the past few years) as Apache 2.0. That license includes an explicit patent grant.